i put in a new 430 watt power supply and when i touch metal at certain places on my case it gives me a little sensation like a 9v battery would. I also have a biometric fingerprint reader hooked thorough usb that is doing the same thing. Andrew Kraker

Something is not grounded properly. You should discontinue use until you figure it out (standoffs, PSU, chasis). It's not a good thing and you may do damage to internal components. As for the question about too much power, the answer simply is no. A PSU is designed to give as much power as needed and nothing more. If the system required more power then the capacitors inside the unit will supply it. You can have too little power but you can't overdo it.

Sounds like you should be checking the line voltage 120v, you need to be certain that what you are plugging into is grounded, I wont try and tell you how to do it with a volt meter however if you have a friend that has a volt meter and knows what to look for have them check your ground at the outlet, there are simple tester you can get at one of the larger hardware chains, it is ment to just plug into the outlet and has a group of leds that will tell you if everything is OKAY line, neutral, ground, they cost about $20.00 Keep the old stuff running